The present invention relates to air to air heat and moisture recovery ventilators and their use to obtain thermally efficient ventilation of buildings and dwellings. Specifically, the present invention relates to an improved rotary wheel heat exchanger mounting arrangement which enables convenient removal of the rotary wheel and/or the exchange media supported by the rotary wheel.
Heat exchangers are used in ventilation systems installed in residential, commercial, and industrial buildings to extract and remove heat and/or moisture from one air stream and transfer the heat and/or moisture to a second air stream. In particular, rotary wheel heat exchangers are known wherein a wheel rotates in a housing through countervailing streams of exhaust and fresh air. In the winter, the heat exchanger extracts heat and moisture from the exhaust stream and transfers the heat and moisture to the fresh air stream while, in the summer, the heat exchanger extracts heat and moisture from the fresh air stream and transfers it to the exhaust stream, preserving building heating/air conditioning while providing desired ventilation.
Conventional commercial, industrial, and residential ventilation systems, such as those illustrated in U.S. Pat. Nos. 5,069,272, 5,183,098, and 5,285,842, utilize rotary heat exchanger wheels having diameters ranging from 25 cm to greater than 100 cm. As heat exchanger wheel size increases, conventional wheel bearings and wheel drive mechanisms are subject to mechanical and operational failure. Accordingly, there is a need for a rotary wheel heat exchanger ventilation system employing an improved heat exchange wheel mounting assembly.
As heat exchanger wheel size increases it is also more difficult and costly to preserve wheel circularity. As wheel circularity degrades, conventional wheel drive mechanisms are less likely to operate properly and ventilation system sealing members are more likely to fail. For example, where a wheel drive roller contacts the outer periphery of a rim body, as is the case with the wheel drive mechanism disclosed in U.S. Pat. No. 5,069,272, it is difficult to maintain roller-to-rim contact if the rim is out of round. Similarly, where a sealing member is provided in contact with the outer periphery of the rim body, it is also difficult to maintain seal-to-rim contact if the rim is out of round. Accordingly, there is a need for a rotary wheel heat exchanger ventilation system employing an improved wheel drive mechanism and mounting assembly. Further, there is a need for a rotary wheel heat exchanger ventilation system wherein wheel drive integrity and ventilation system efficiency are preserved where wheel circularity degrades.
Conventional commercial, industrial, and residential ventilation systems utilizing rotary heat exchanger wheels operate most efficiently if the heat exchange media is cleaned or replaced regularly. The mechanical arrangements of some of the conventional systems make removal and/or cleaning of the heat exchange media difficult and time consuming. Accordingly, there is also a need for a ventilation system which provides for convenient and efficient heat exchange media removal for replacement or cleaning.
Although some of the conventional ventilation systems discussed above transfer moisture as well as heat from an exhaust stream to a fresh air stream, e.g., see U.S. Pat. Nos. 5,069,272 and 5,285,842, these conventional systems rely upon the heat exchange media alone to effect transfer of the moisture. Accordingly, there is a need for a ventilation system which includes a supplemental moisture transfer mechanism.